Neutron collar calibration and evaluation for assay of LWR fuel assemblies containing burnable neutron absorbers

Henriksen, P.W.; Menlove, H.O.; Stewart, J.E.; Qiao, Shuang; Wenz, Tracy R.; Verrecchia, G.P.D.

doi:10.2172/6531379

Cited by 37 publications

(60 citation statements)

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“…The Uranium Neutron Coincidence Collar (UNCL) is used by the International Atomic Energy Agency (IAEA) for verification of the mass of 235 U in low-enriched U fuel assemblies [Menlove 1981;Menlove 1990]. It consists of either three or four banks of detectors surrounding a central cavity where the fuel assembly is placed during measurements.…”

Section: Coincidence Counting With Boron-based Alternative Neutron Dementioning

confidence: 99%

“…It consists of either three or four banks of detectors surrounding a central cavity where the fuel assembly is placed during measurements. The original UNCL (referred to in this report as the "UNCL-I") received an update in design (known as the UNCL-II) in 1989 to reduce measurement times and incorporate new electronics, though the UNCL-I is still used in some applications [Menlove 1990]. Since pressurized water reactor (PWR) and boiling water reactor (BWR) fuel assemblies have different cross-sections, both the UNCL-I and UNCL-II each use different geometries and numbers of tubes for measuring PWR and BWR fuel assemblies.…”

Section: Coincidence Counting With Boron-based Alternative Neutron Dementioning

confidence: 99%

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Neutron Coincidence Counting Studies

Rogers¹,

Ely²,

Kouzes³

et al. 2012

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Section: Coincidence Counting With Boron-based Alternative Neutron Dementioning

confidence: 99%

Section: Coincidence Counting With Boron-based Alternative Neutron Dementioning

confidence: 99%

Neutron Coincidence Counting Studies

Rogers¹,

Ely²,

Kouzes³

et al. 2012

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“…There have been two generations of UNCL assemblies, the original UNCL (referred to in this report as the "UNCL-I") was designed before 1981 [Menlove 1981], and the UNCL-II was introduced in 1989 [Menlove et al 1990]. The difference between the two versions is in the number of tubes, adjustability of the "collar," and some other design details.…”

Section: Acronyms and Abbreviationsmentioning

confidence: 99%

“…Both the UNCL-I and the UNCL-II were developed at Los Alamos National Laboratory (LANL), and they differ mostly in the number of 3 He tubes used. The models were created using the dimensional information provided by LANL [Menlove 1981;Menlove et al 1990] for the UNCL-II and from Canberra Industries literature [Canberra 2011] for the UNCL-I.…”

Section: Uncl Modelsmentioning

confidence: 99%

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Uranium Neutron Coincidence Collar Model Utilizing 3He

Siciliano¹,

Rogers²,

Schweppe³

et al. 2012

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Executive SummaryThe Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project "Coincidence Counting With Boron-Based Alternative Neutron Detection Technology" at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate an alternative system based upon boron-lined proportional tubes in a configuration typical for 3 He-based coincidence counter applications.The specific application selected for boron-lined tube replacement in this project was one of the Uranium Neutron Coincidence Collar (UNCL) designs. This report, providing results for model development of a UNCL, is a deliverable under Task 2 of the project.The current UNCL instruments utilize 3 He tubes. As the first step in developing and optimizing a boron-lined proportional counter based version of the UNCL, models of eight different 3 Hebased UNCL detectors currently in use were developed and evaluated. Neutron-count efficiencies and corresponding die-away times from those eight modeled systems are reported, and compared to measurements for those systems with values reported in the literature. The reported experimental measurements for efficiencies and die-away times agree to within 10%.

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Principles of Neutron Coincidence Counting

Swinhoe,

Ensslin,

Hutchinson

et al. 2024

Nondestructive Assay of Nuclear Materials for Safeguards and Security

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This chapter describes the principles involved with using neutron coincidences that obtain more information about a measured sample than through singles counting alone. The chapter describes the origin of neutron correlations and how they manifest themselves in the neutron pulse train from a detector. The Rossi-α distribution is presented. The chapter then describes measurement and analysis methods used to extract and analyze correlated counting rates, such as the Feynman variance to mean method and the shift register coincidence circuit. These methods can be used to estimate fission rate and neutron multiplication. Dead time corrections, multiple pulsing and the uncertainties resulting from counting statistics are presented. Several passive methods for the determination of 240Pueffective mass are presented in detail: ‘passive calibration curve’, ‘known alpha’ and ‘known multiplication’. This is followed by a description of active coincidence methods, in which an external neutron source is used to induce fission in the item of interest. This section includes a discussion of the selection of the external source, the use of fast and thermal interrogation modes and a presentation of measurement uncertainties. One example is given of an active technique to measure uranium linear density and burnable poison simultaneously.

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Neutron collar calibration and evaluation for assay of LWR fuel assemblies containing burnable neutron absorbers

Cited by 37 publications

References 1 publication

Neutron Coincidence Counting Studies

Neutron Coincidence Counting Studies

Uranium Neutron Coincidence Collar Model Utilizing 3He

Principles of Neutron Coincidence Counting

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